Continuous and non-invasive estimation of arterial blood pressure (BP) without using a cuff has gained emerging interest for health care applications. Instead of commonly used cuff-based measurements, changes in the Pulse Wave Velocity (PWV), i.e., the speed of a pressure pulse propagating along the arterial wall, can be an alternative approach for a continuous, non-invasive and indirect BP measurement, as for example described in “Continuous blood pressure measurement by using the pulse transit time: comparison to a cuff-based method”, by H. Gesche et al., European Journal of Applied Physiology, vol. 112, no. 1, pp. 309-315, 2012, Springer-Verlag. PWV depends both on the arterial pressure and the intrinsic elastic properties of the arterial wall. Although this relationship is very well defined in a theoretical framework, it is practically difficult to have an accurate estimate of the relationship between PWV and BP since external factors like ageing with its related diseases, cardiovascular risk factors and others can significantly influence arterial wall stiffness.
As a surrogate of PWV, an indirect estimation of BP can be also obtained with the use of Pulse Transit Time (PTT), i.e., the time delay between the R-wave of the ECG and the arrival of the pulse wave measured in a peripheral position, as for example described in “Wearable Cuff-less PTT-based System for Overnight Blood Pressure Monitoring”, by Yali Zheng et al., Engineering in Medicine and Biology Society (EMBS), 35th Annual International Conference of the IEEE EMBS, pp. 6103-6106, Osaka 3-7 Jul. 2013.
There is a motivation to improve current state of the art electronic systems and methods for non-invasive, cuffless blood pressure estimation.